Assay and culture tray

ABSTRACT

A PLATE OR TRAY SUITABLE FOR ASSAY AND CELL AND TISSUE CULTURE ON A MINIATURE SCALE COMPRISES A TRANSPARENT BASE MEMBER MADE OF PLASTIC AND HAVING EXTENDING UPWARD THEREFROM A PLURALITY OF PARRALLEL ROWS OF OPEN TOP CYLINDRICAL WELLS SPACED APART FROM EACH OTHER A SUFFICIENT DISTANCE TO AVOID CROSS-CONTAMINATION, AN INTERGRAL PERIPHERAL UPSTANDING WALL TERMINATING IN A FLANGE PROVIDED WITH A SEAT ADAPTED TO RECEIVE AND SERCURE A LID HAVING A DOWNWARDLY EXTENDING WALL ADAPTED TO ENGAGAE THE FLANGE PORTTION OF THE PLATE, WHICH LID MAY INCLUDE A PLURALITY OF PARRALLEL ROWS OF DOWNWARDLY EXTENDING WELL SEALS POSITINED TO ENGAGE THE MOUTH PORTIONS OF THE WELLS TO FORM CLOUSURES THEREFOR.

March 14, 1972 A. E. FREEMAN ASSAY AND CULTURE TRAY 2 Sheets-Sheet 1Filed Dec. 5. 1969 INVENTOR .I ffii:

IIIII L T AARON E. FREEMAN FIG. 3

Mardi 14, 1972 A, E, FREEMAN 3,649,464

ASSAY AND CULTURE TRAY Filed Dec. 5, 1969 2 Sheets-Sheet 2 FIG. I

INVENT OR AARON E. FREEMAN By a ATTORNEY United States Patent 3,649,464ASSAY AND CULTURE TRAY Aaron E. Freeman, Rockville, Md., assignor toMicrobiological Associates, Inc., Bethesda, Md. Filed Dec. 5, 1969, Ser.No. 882,493 Int. Cl. C12k 1/00 U.S. Cl. 195-140 15 Claims ABSTRACT OFTHE DISCLOSURE A plate or tray suitable for assay and cell and tissueculture on a miniature scale comprises a transparent base member made ofplastic and having extending upward therefrom a plurality of parallelrows of open top cylindrical wells spaced apart from each other asuicient distance to avoid cross-contamination, an integral peripheralupstanding wall terminating in a flange provided with a seat adapted toreceive and sercure a lid having a downwardly extending wall adapted toengage the flange portion of the plate, which lid may include aplurality of parallel rows of downwardly extending well seals positionedto engage the mouth portions of the wells to form closures therefor.

BACKGROUND OF THE INVENTION The rapid expansion of cell and tissueculture, particularly in the iield of virology, has made necessary theprocessing of large numbers of individual cultures by macrotechniques,employing standard size Petri dishes and other culture vessels. The needfor subsequent virus isolation, titration, and assay tests and the like,has involved the handling and manipulation of large numbers of culturevessels and the transfer of substantial volumes of media with attendantspace requirements, and hazards of spillage and contamination.

Efforts have been made by virologists and others engaged in cell andtissue culture to utilize for growth, virus assay, neutralization andtoxicity tests and the like, the currently available miniature titrationor assay plates. These plates are designed for complement-fixation andother serological tests and have proved to be poorly adaptable andgenerally inadequate for cell and tissue culture purposes. Such assay ortitration plates customarily cornprise a one piece molded plastic shellincluding a plurality of parallel rows of uniformly arranged cups whichdepend downwardly from a top wall which contains the open upper ends ofthe cups, tangentially disposed to each other, the closed lower endsbeing individually formed at the bottoms of the respective cups. When itis attempted to utilize such assay plates for cell and tissue culturepurposes, one drawback is the possible cross-contamination of viruses,reagents and cells from one cup or well to another because of thearrangement of the cups whereby the fact that their openings are flushwith the top wall surface permits any spillage to llow from one cup intoanother, which spillage may even result in possible contamination of anentire incubator where the plate is being used in an incubator.

The commercially available miniature titration plates employ a standardtype of tape sealing system to cover the well openings and when aneifort is made to use such plates for cell or tissue culture purposes,the tape presents the danger of causing cross-contamination through amechanical action.

Accordingly, there has existed a need for a cell and tissue culture andassay plate, particularly adapted for cell and tissue culture andattendant assays on a miniature scale and which would be free from thedrawbacks of other types of plates not designed specifically for celland tissue culture purposes.

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GENERAL DESCRIPTION OF THE INVENTION In accordance with the presentinvention, there is provided a novel cell and tissue culture and assayplate, capable of multiple culturing or assaying on a miniature scale,together with a special lid or cover therefor.

The miniature plate of the invention comprises a transparent integralmolded base from which there extend upward a multiplicity of small cupsor wells arranged in rows, which are capable of functioning as culturevessels for cell or tissue culture, or as cups for microassay work. Theouter walls of the cups or wells protrude upward, and are spaced apartfrom each other, and are not adjoined by an upper wall surface, therebyeliminating the possibility of spillage flowing from one well toanother, by reason of the troughs made between adjacent cups or wells.This serves to prevent cross-contamination when the cups are employedfor cell or tissue culture Work. The plate is also provided with anupstanding peripheral wall which forms a trough with the bottom of theplate and serves to prevent external spillage.

These and other novel features and advantages of the plate of theinvention will be better understood by reference the accompanyingdrawings, in which:

FIG. 1 is a top plan View of the miniculture plate showing thearrangement of the cups or wells;

FIG. 2 is a section taken through the plate of FIG. l, taken along theline 2 2 of FIG. 1;

FIG. 3 is a top plan View of a particular form of the lid or cover;

FIG. 4 is a cross-sectional view of the lid of FIG. 3 taken along theline 4 4;

FIG. 5 is a cross-sectional view of another form of the lid or coverprovided with well-sealing means;

FIG. 6 is a view in perspective of a type of well sealing means;

FIG. 7 is a cross-sectional view showing the interrelationship of twostacked trays;

FIG. 8 is a cross-sectional view showing the interrelationship of a traycovered with a lid and a second tray superimposed thereon; and

FIG. 9 is a View in perspective of the bottom of a tray showing theperipheral bead thereon.

Referring now to the drawings, IFIG. 1 illustrates a presently preferredembodiment of the in'vention, in which the miniature culture or assayplate is shovm generally at 10, and includes a bottom tray 11 from whichthere extend upward `a plurality of rows of cups or wells 12, eachhaving a thin `wall 13. These cup walls are spaced apart from each otherto form troughs between them and to avoid any danger ofcross-contamination of the individual cups or wells by reason ofspillage or overflow of the well contents. The cups are of equal depthand diameter. Thus, for example, the typical dimension of a well is kawall height of approximately l0 mm., the wall having an inside diameterof approximately 7.5 mm. The space between adjacent outside Wallsurfaces is Iafbout 1 mm. which will ordinarily suffice to avoid thecross-contamination referred to above. The cups may be of any desiredshape, but are preferably cylindrical.

The plate is preferably integrally molded of `a suitable transparentplastic material, for example a vinyl resin material, or methylmethacrylate type material, which exhibits high mechanical strength,light weight, is readily cleaned if the plate is to be re-used, andwhich is suiciently inexpensive so that the plate (and cover) may betreated as disposable.

In the embodiment shown in FIG. 1, the general dimensions of the plateor tray will typically comprise, for example, an over-all length ofabout 124 mm., and a width of about 80 mm. One corner of the plate isprovided with a cut-oil beveled edge 14. This permits design of the lidto have the same configuration as the plate itself, and forces the userto replace the lid in its original position, eliminating cntaminationand other difficulties which might arise from replacing the lid in thewrong position.

In the preferred embodiment shown in FIG. l, there are 12 rows of cupsor wells, each row containing 8 cups, providing a total of 96. However,it will be understood that the number of cups and their arrangement maybe varied yas circumstances require. The trav 11 may be, for example,about 3 mm. thick.

Referring to FIG. 2, there extends peripherally around the edge of thetray 11 an upstanding wall 15, which is molded integrally therewith, themain portion of which wall advantageously has an over-all height equalto approximately one-half the height of the cups or wells, i.e. about 5mm., but this is not critical. The wall terminates in an integral iiange16, having a `seat 17 formed by an extension of the Awall which servesto seat and secure the lid 20, as described below.

Por purposes of tray stacking, the tray 11 of the plate is provided witha downwardly extending peripheral bead or lug 18, which is adapted totit around and encompass the outer limit of the array of wells 19 sothat when one tray is stacked on top of another without the lid 20, theupper tray is anchored and cannot slide off. The bead 18, in addition topermitting stacking of the plates, also serves to prevent the bottom ofthe plate from being scratched when laid on a surface, thus preservingits optical qualities. The arrangement of 4bead 18 will be more clearlyunderstood by reference to FIG. 9.

The microculture plate of the invention may be provided with a suitablelid or cover, the basic version of which is illustrated in FIGS. 3 and4. The lid 20 is advantageously made of transparent plastic material,and is integrally molded. It includes a substantially at wall 21, whichmerges into a downwardly extending peripheral wall 22 as shown in FIGS.4 and 5. The lid is so designed that the wall height is sufficient, whenthe lid is seated over the miniculture plate 10, to provide a clearancebetween t-he tops 19 of the wells 12 and the lower surface 21a of thelid wall 21. Typically, 'such clearance may be, for example, about 2 to3 mm. The lid has a conliguration matching that of the plate itself,that is, it is provided with the cut-off or bevel corner 23, to engagethe plate in a single position. In the embodiment shown in FIGS. 3 and4, the lid wall terminates in a ange portion 24, as shown in TIG. 4,having an inner lug 25, to engage the edge of the ange 16 and the seat17 at the upper end of the plate Wall 15. This minimizes possiblecontamination.

This tray stacking principle is illustrated more clearly in FIG. 7,showing the inter-relationship of the bead 18 and the wells 19, withrespect to the wall ange portions 16 and 17, the function of the bead 18here being to prevent lateral sliding of the upper tray. When trays arethus stacked, the wells can be sealed with the sealing strip illustratedin FIG. 6, and described below.

-Extending upward from the lid wall 21 is a peripheral lug 26 whichserves to engage the downwardly extending bead 18 of the plate 10, whena set of plates and lids is stacked. This principle is illustrated inFIG. 8. When the lid is applied to the tray, the outer edge of the lidperipheral wall 22 does not extend beyond the edge of flange 16 of thetray, so that the protruding iiange portion 16 of the tray permitsgrasping and lifting of the tray without the danger of grasping the lidand having the tray drop ott. I

In a modied version of the lid shown in FIG. 5, there are providedintegrally molded well seals 27, which extend downwardly from the lidwall 21, in a number matching the number of cups or wells, andpositioned so as to engage the mouth portion 19 of the wells bypenetrating into the well openings. For this purpose the well seal walls28 are tapered so that they wedge into the well, providing a positiveseal.

The form of well seal shown in FIG. 6 is intended to be used as thesealing means for a given row of wells, or to be used in conjunctionwith the form of lid shown in FIG. 4. It comprises ya strip 30 of atransparent plastic material having integrally molded therein a set of12 or 8 individual well seals 31 which are adapted to extend into themouths 19 of the individual wells. The well seals 31 advantageously havetapering walls of the type described in connection with the embodimentof FIG. 5. The strip may be utilized so that the S rows of 12 wells canbe sealed individually, or conversely, if an 8-seal strip is used, sothat the 12 rows of 8 each can be thus sealed. In this way the user canremoive the sealing strip from one row at a time without unsealing theremaining 7 or 11 rows of wells. Tab 32 forming one end of strip 30 isprovided for this purpose.

What is claimed is:

1. A cell and tissue culture and assay plate comprising a transparentsubstantially planar base member having integrally molded therein andextending upward therefrom a plurality of parallel rows of upstandingopen top cups or wells, said wells being spaced apart from each other toform troughs between them and to avoid cross-contamination of the wellcontents, said base member including a peripheral upstanding wallintegral therewith, and means at the upper end of said wall adapted toreceive a lid or cover.

2. The plate according to claim 1, in which said plate is made of atransparent plastic material.

3. The plate according to claim 1, in -which said wells are arranged intransversely aligned rows containing an equal number of Wells.

4. The plate according to claim 1, in which said peripheral wall forms atrough with the bottom of the plate.

5. The plate according to claim 1, in which the height of saidperipheral wall is less than the height of said wells.

6. The plate according to claim 1, in which the height of saidperipheral wall is approximately one-half the height of Isaid wells andwherein said plate includes a lid secured to said means at the upper endof said wall.

7. The plate according to claim 1, in which said peripheral wallterminates in an integral ange provided with a seal adapted to receive alid or cover.

8. The plate accor-ding to claim 1, which includes a downwardlyextending peripheral bead adapted to prevent scratching of the bottom ofthe plate and to permit stacking upon another plate or upon the lid orcover of a plate.

9. The plate according to claim 8, in which said peripheral bead isadapted to tit around the outer limit of the cups or wells.

10. The plate according to claim 1, which includes, in combination, alid comprising a transparent substantially planar member including aperipheral downwardly depending wall integral therewith, the lower edgeof said wall including a ange portion adapted to seat and secure the lidin the receiving portion of said plate wall, the wall of said lid beingof suliicient height to provide a clearance between the bottom surfaceof the lid and the upper ends of the wells.

11. The plate according to claim 6, in which both the plate and the lidare provided with a matching cut-off corner portion to align said plateand lid in predetermined position.

12. The plate according to claim 6, in which said lid includes aplurality of parallel rows of integral well seals extending downwardlyfrom the inner surface of the lid, said seals being positioned toregister with and to engage the mouth portions of the wells to formclosures therefor.

13. The plate according to claim 6, in which said lid includes aperipheral upwardly extending bead positioned adjacent the outer edge ofthe upper surface of the lid, and which is adapted to engage theperipheral bead extending downwardly from the bottom edge of a similarplate, when plate is stacked or superimposed thereon.

5 6 14. The plate according to claim 1, in which the mouths ReferencesCited of said wells are sealed with a exible strip sealing mem- UNITEDSTATES PATENTS ber including a plurality of intgeral well sealspositioned to register with and to engage the mouth portions of said3,356,452 12/1967 Cooke et al 23"292 lltof lo thf, t"1d'dghingfagrefnbes ere or sald s p mc mg a e 5 A.LoU1s MoNACELLPnmaryExaminer 15. The plate according to claim 6, in which the outer R, M,ELLIOTT, Assistant Examiner edge of the lid peripheral wall does notextend beyond the U S Cl X R surface said peripheral plate wall topermit lifting of the plate and lid simply by grasping the plate edge.10 23--292z 220-21

